Title: Machine for printing on cylindrical or frusto-conical containers with ultra-violet-light-setting ink

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Abstract: A machine for printing on containers in ultra-violet-light-setting ink has a turret fitted with rotatable mandrels for supporting the containers, the axes of the mandrels being radial relative to the axis of the turret, indexing mechanism for intermittently turning the turret to register each mandrel in succession with printing cylinders spaced around the turret, and gear unit for rotating the mandrels and printing cylinders in synchronism. The turret has a cylindrical rim with flat annular upper and lower surfaces, and each mandrel is mounted in a recess in the rim with the recess opening through the lower surface to permit engagement with the printing cylinders and opening through the periphery of the rim to enable containers to be mounted on the mandrels. Ultra-violet light sources are arranged to direct light into the recesses to set ink printed on containers on the mandrels, and the light sources are provided with shrouds which co-operate with the rim to prevent escape of the ultra violet light except into a recess. The light sources may be fixed in which case the shrouds are spaced close to the surfaces of the rim. Alternatively, the light sources and shrouds may be fixed on the turret. The printing cylinders are twice the diameter of the containers and fitted with a printing plate which extends only half way around the cylinder, the surface of the cylinder being spaced below the lower surface of the turret rim, the printing plate having a thickness such that it extends into the recess during printing, and the indexing mechanism being synchronised with rotation of the cylinders so that the printing plate is on the underside of the cylinder during indexing movements of the turret. The recesses may open through the upper surface of the turret rim and a light source arranged to direct light downwards onto a container while the container is being printed through the opening in the lower surface of the rim, so that the ink on the leading edge of an image printed on the container will be cured before the trailing edge is printed, whereby the trailing edge can overprint the leading edge without risk of smudging the ink.


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